Functional Neurosurgery and Experimental Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
Curr Biol. 2012 Mar 6;22(5):403-7. doi: 10.1016/j.cub.2012.01.024. Epub 2012 Feb 2.
Voluntary movement is accompanied by changes in the degree to which neurons in the brain synchronize their activity within discrete frequency ranges. Two patterns of movement-related oscillatory activity stand out in human cortical motor areas. Activity in the beta frequency (15-30 Hz) band is prominent during tonic contractions but is attenuated prior to and during voluntary movement. Without such attenuation, movement may be slowed, leading to the suggestion that beta activity promotes postural and tonic contraction, possibly at a cost to the generation of new movements. In contrast, activity in the gamma (60-90 Hz) band increases during movement. The direction of change suggests that gamma activity might facilitate motor processing. In correspondence with this, increased frontal gamma activity is related with reduced reaction times. Yet the possibility remains that these functional correlations reflect an epiphenomenal rather than causal relationship. Here we provide strong evidence that oscillatory activities at the cortical level are mechanistically involved in determining motor behavior and can even improve performance. By driving cortical oscillations using noninvasive electrical stimulation, we show opposing effects at beta and gamma frequencies and interactions with motor task that reveal the potential quantitative importance of oscillations in motor behavior.
自愿运动伴随着大脑神经元在离散频率范围内同步活动的程度的变化。在人类皮质运动区中，两种与运动相关的振荡活动模式引人注目。在紧张收缩期间，β 频带（15-30 Hz）的活动很突出，但在自愿运动之前和期间会减弱。如果没有这种衰减，运动可能会减慢，导致β 活动促进姿势和紧张收缩的建议，可能会对新运动的产生造成代价。相比之下，γ 频带（60-90 Hz）的活动在运动期间增加。变化的方向表明γ 活动可能有助于运动处理。与此相对应的是，额叶γ 活动的增加与反应时间的减少有关。然而，这些功能相关性仍然可能反映出偶发现象而不是因果关系。在这里，我们提供了强有力的证据，表明皮层水平的振荡活动在确定运动行为方面具有机制性作用，甚至可以提高性能。通过使用非侵入性电刺激来驱动皮层振荡，我们展示了β 和γ 频率的相反效果，以及与运动任务的相互作用，揭示了振荡在运动行为中的潜在定量重要性。
